ffx_util.h

// This file is part of the FidelityFX SDK.
//
// Copyright (C) 2024 Advanced Micro Devices, Inc.
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files(the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and /or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions :
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// THE SOFTWARE.

#pragma once

#include <FidelityFX/host/ffx_types.h>

/// @defgroup Utils Utilities
/// Utility Macros used by the FidelityFX SDK
/// 
/// @ingroup ffxHost

/// The value of Pi.
///
/// @ingroup Utils
const float FFX_PI = 3.141592653589793f;

/// An epsilon value for floating point numbers.
///
/// @ingroup Utils
const float FFX_EPSILON = 1e-06f;

/// Helper macro to create the version number.
///
/// @ingroup Utils
#define FFX_MAKE_VERSION(major, minor, patch) ((major << 22) | (minor << 12) | patch)

///< Use this to specify no version.
///
/// @ingroup Utils
#define FFX_UNSPECIFIED_VERSION     0xFFFFAD00

/// Helper macro to avoid warnings about unused variables.
///
/// @ingroup Utils
#define FFX_UNUSED(x)               ((void)(x))

/// Helper macro to align an integer to the specified power of 2 boundary
///
/// @ingroup Utils
#define FFX_ALIGN_UP(x, y)          (((x) + ((y)-1)) & ~((y)-1))

/// Helper macro to check if a value is aligned.
///
/// @ingroup Utils
#define FFX_IS_ALIGNED(x)           (((x) != 0) && ((x) & ((x)-1)))

/// Helper macro to compute the rounded-up integer division of two unsigned integers
///
/// @ingroup Utils
#define FFX_DIVIDE_ROUNDING_UP(x, y) ((x + y - 1) / y)

/// Helper macro to stringify a value.
///
/// @ingroup Utils
#define FFX_STR(s)                  FFX_XSTR(s)
#define FFX_XSTR(s)                 #s

/// Helper macro to forward declare a structure.
///
/// @ingroup Utils
#define FFX_FORWARD_DECLARE(x)      typedef struct x x

/// Helper macro to return the maximum of two values.
///
/// @ingroup Utils
#define FFX_MAXIMUM(x, y)           (((x) > (y)) ? (x) : (y))

/// Helper macro to return the minimum of two values.
///
/// @ingroup Utils
#define FFX_MINIMUM(x, y)           (((x) < (y)) ? (x) : (y))

/// Helper macro to do safe free on a pointer.
///
/// @ingroup Utils
#define FFX_SAFE_FREE(x, freeFunc) \
    do {                 \
        if (x)           \
        {                \
            freeFunc(x); \
            x = nullptr; \
        }                \
    } while (false)

/// Helper macro to return the abs of an integer value.
///
/// @ingroup Utils
#define FFX_ABSOLUTE(x)                 (((x) < 0) ? (-(x)) : (x))

/// Helper macro to return sign of a value.
///
/// @ingroup Utils
#define FFX_SIGN(x)                     (((x) < 0) ? -1 : 1)

/// Helper macro to work out the number of elements in an array.
///
/// @ingroup Utils
#define FFX_ARRAY_ELEMENTS(x)           (int32_t)((sizeof(x) / sizeof(0 [x])) / ((size_t)(!(sizeof(x) % sizeof(0 [x])))))

/// The maximum length of a path that can be specified to the FidelityFX API.
///
/// @ingroup Utils
#define FFX_MAXIMUM_PATH                (260)

/// Helper macro to check if the specified key is set in a bitfield.
///
/// @ingroup Utils
#define FFX_CONTAINS_FLAG(options, key) (((options) & key) == key)

#if defined(FFX_MUTEX_IMPL_SHARED)
/// Lock mutex exclusively.
///
/// @ingroup Utils
#define FFX_MUTEX_LOCK(x)               x.lock()
/// Lock mutex for shared access.
///
/// @ingroup Utils
#define FFX_MUTEX_LOCK_SHARED(x)        x.lock_shared()
/// Unlock exclusive mutex lock.
///
/// @ingroup Utils
#define FFX_MUTEX_UNLOCK(x)             x.unlock()
/// Unlock shared mutex lock.
///
/// @ingroup Utils
#define FFX_MUTEX_UNLOCK_SHARED(x)      x.unlock_shared()
#elif defined(FFX_MUTEX_IMPL_STANDARD)
/// Lock mutex exclusively.
///
/// @ingroup Utils
#define FFX_MUTEX_LOCK(x)               x.lock()
/// Lock mutex for shared access.
///
/// @ingroup Utils
#define FFX_MUTEX_LOCK_SHARED(x)        FFX_MUTEX_LOCK(x)
/// Unlock exclusive mutex lock.
///
/// @ingroup Utils
#define FFX_MUTEX_UNLOCK(x)             x.unlock()
/// Unlock shared mutex lock.
///
/// @ingroup Utils
#define FFX_MUTEX_UNLOCK_SHARED(x)      FFX_MUTEX_UNLOCK(x)
#elif !defined(FFX_MUTEX_LOCK) || !defined(FFX_MUTEX_LOCK_SHARED) || !defined(FFX_MUTEX_UNLOCK) || !defined(FFX_MUTEX_UNLOCK_SHARED)
#error When using custom mutex you have to provide all following operations too: FFX_MUTEX_LOCK, FFX_MUTEX_LOCK_SHARED, FFX_MUTEX_UNLOCK, FFX_MUTEX_UNLOCK_SHARED!
#endif // #if defined(FFX_MUTEX_IMPL_SHARED)

/// Computes the number of bits set to 1 in a integer.
///
/// @param [in] val Integer mask.
///
/// @return Number of bits set to 1 in provided val.
///
/// @ingroup Utils
inline uint8_t ffxCountBitsSet(uint32_t val) noexcept
{
#if __cplusplus >= 202002L
    return static_cast<uint8_t>(std::popcount(val));
#elif defined(_MSVC_LANG)
    return static_cast<uint8_t>(__popcnt(val));
#elif defined(__GNUC__) || defined(__clang__)
    return static_cast<uint8_t>(__builtin_popcount(val));
#else
    uint32_t c = val - ((val >> 1) & 0x55555555);
    c = ((c >> 2) & 0x33333333) + (c & 0x33333333);
    c = ((c >> 4) + c) & 0x0F0F0F0F;
    c = ((c >> 8) + c) & 0x00FF00FF;
    return static_cast<uint8_t>(((c >> 16) + c) & 0x0000FFFF);
#endif
}